BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER...

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http://www.iaeme.com/IJMET/index.asp 363 [email protected] International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 11, November 2017, pp. 363–367, Article ID: IJMET_08_11_040 Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical science, Hindustan institute of technology and science S. Pragadheswaran ACE College of Engineering ABSTRACT: To carry out the buckling analysis of landing gear, CAD model is imported to MSC Patran which is meshed by ISOMESH. Material property is assigned to the meshed element followed by application of loads and boundary condition. Static load is applied in the bottom of strut and it is found that landing gear does not buckle for the applied load. From the analysis buckling factor is used to calculate the load for which landing gear buckles and the same is verified using the software. Keywords: Landing gear, buckling, MSC PATRAN, Strut, Static loading. Cite this Article: G Krishnaveni, E.S Elumalai, S.Mayakkannan and S. Pragadheswaran, Buckling Analysis of Nose Landing Gear Under Static Condition, International Journal of Mechanical Engineering and Technology 8(11), 2017, pp. 363–367. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11 1. INTRODUCTION: Landing gear in aircraft is a critical subsystem which is used to provide suspension during taxi, take-off and landing. It reduces the impact loads being transferred to other parts of aircraft by absorbing and dissipating the kinetic energy of landing. Both main landing gear and nose landing gear have many structural components like main fitting, axle, trailing arm, torque links etc. and system components like brake system, retraction antiskid systems with few more components in nose landing gear. Landing gear is subjected to number of critical loads so design of landing gear against buckling plays an important role. However this paper deals with only the static load before take-off of an aircraft. 2. GEOMETRY: It is predicted that 50% of accidents which occurs in aircraft are due to failure of Landing gear. Hence proper design of landing gear is very important with minimum weight and volume. In order to suit the take-off and landing altitudes, tip over and general airframe configuration requirements, the position of C.G and length is generally determined using the

Transcript of BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER...

Page 1: BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical

http://www.iaeme.com/IJMET/index.asp 363 [email protected]

International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 11, November 2017, pp. 363–367, Article ID: IJMET_08_11_040

Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11

ISSN Print: 0976-6340 and ISSN Online: 0976-6359

© IAEME Publication Scopus Indexed

BUCKLING ANALYSIS OF NOSE LANDING

GEAR UNDER STATIC CONDITION

G Krishnaveni, E.S Elumalai, S.Mayakkannan

School of aeronautical science, Hindustan institute of technology and science

S. Pragadheswaran

ACE College of Engineering

ABSTRACT:

To carry out the buckling analysis of landing gear, CAD model is imported to

MSC Patran which is meshed by ISOMESH. Material property is assigned to the

meshed element followed by application of loads and boundary condition. Static load

is applied in the bottom of strut and it is found that landing gear does not buckle for

the applied load. From the analysis buckling factor is used to calculate the load for

which landing gear buckles and the same is verified using the software.

Keywords: Landing gear, buckling, MSC PATRAN, Strut, Static loading.

Cite this Article: G Krishnaveni, E.S Elumalai, S.Mayakkannan and S.

Pragadheswaran, Buckling Analysis of Nose Landing Gear Under Static Condition,

International Journal of Mechanical Engineering and Technology 8(11), 2017,

pp. 363–367.

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11

1. INTRODUCTION:

Landing gear in aircraft is a critical subsystem which is used to provide suspension during

taxi, take-off and landing. It reduces the impact loads being transferred to other parts of

aircraft by absorbing and dissipating the kinetic energy of landing. Both main landing gear

and nose landing gear have many structural components like main fitting, axle, trailing arm,

torque links etc. and system components like brake system, retraction antiskid systems with

few more components in nose landing gear. Landing gear is subjected to number of critical

loads so design of landing gear against buckling plays an important role. However this paper

deals with only the static load before take-off of an aircraft.

2. GEOMETRY:

It is predicted that 50% of accidents which occurs in aircraft are due to failure of Landing

gear. Hence proper design of landing gear is very important with minimum weight and

volume. In order to suit the take-off and landing altitudes, tip over and general airframe

configuration requirements, the position of C.G and length is generally determined using the

Page 2: BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical

Buckling Analysis of Nose Landing Gear Under Static Condition

http://www.iaeme.com/IJMET/index.asp 364 [email protected]

position of C.G. this paper deals with modelling of nose landing gear. The design of nose

landing gear consists of components like main strut, lower strut (piston) and lug attachment

figure [1].

Figure 1 Nose landing gear (All dimensions are in mm)

The model is designed as shown below Fig.2. The model is further imported to software

MSC.PATRAN for buckling analysis. It is meshed using ISOMESH. The no of elements are

as follows. MSC PATRAN is used for pre-processing and post processing purpose and MSC

NASTRAN is used as solver.

No of 2D elements (quad4) = Elm 1:102 = 102

No of 3D elements (Hex 8) = Elm 362:4061 = 3700

No of 3D elements (Wedge) = Elm 4062:5321 = 1260

Total no of elements in the model is = 5062

Figure 2 Meshed model

Page 3: BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical

G Krishnaveni, E.S Elumalai, S.Mayakkannan and S. Pragadheswaran

http://www.iaeme.com/IJMET/index.asp 365 [email protected]

3. MATERIAL PROPERTIES:

The material selected here is Titanium Ti5553 alloys. Isotropic material property (titanium) is

assigned to meshed elements. The physical properties of titanium are as follows.

Table 1 Physical Properties

Sl.

no. Physical property value

1 Young’s modulus E 115GPa

2 Ultimate tensile strength 1236MPa

3 Poisons ratio 0.32

4 Yield strength 1174MPa

5 Density- 4650kg/mm3

4. LOADS AND BOUNDARY CONDITION:

Loads and boundary conditions are applied to meshed elements. Since the lugs are 2D and

fixed to fuselage we arrest all six degrees of freedom. Boundary condition is as shown below.

Figure 3 Boundary condition

Next step is the application of load. Main landing gear takes 80-85% of load whereas nose

landing gear takes 15-20% of load. Static load to be applied on nose landing gear is 98590.5N

(from weight of aircraft).Point load is to be applied on the bottom of strut which has 81

elements hence load of 1221.61N is to applied in each node as shown below.

Page 4: BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical

Buckling Analysis of Nose Landing Gear Under Static Condition

http://www.iaeme.com/IJMET/index.asp 366 [email protected]

Figure 4 Load condition

5 RESULTS:

MSC NASTRAN is used as solver and results shows that the given model does not buckle by

factor of 415.58 (Figure 5).

Figure 5 Model does not buckle

Load calculation is done using the above result and is found to be 41121848.79N, now

load of 507677.146N is applied on each node and the analysis carried out again.

Page 5: BUCKLING ANALYSIS OF NOSE LANDING GEAR …€¦ · BUCKLING ANALYSIS OF NOSE LANDING GEAR UNDER STATIC CONDITION G Krishnaveni, E.S Elumalai, S.Mayakkannan School of aeronautical

G Krishnaveni, E.S Elumalai, S.Mayakkannan and S. Pragadheswaran

http://www.iaeme.com/IJMET/index.asp 367 [email protected]

Figure 6 buckling factor 1

CONCLUSION AND FUTURE WORK:

Hence the buckling load is calculated for the model and verified using the software. It is thus

concluded that landing gear will not buckle for any load below 41121848.79N when it is at

static condition before take-off. Landing gear is subjected to high impact forces during

landing, hence dynamic loading including all the forces should be applied to find buckling

force during landing, which requires load spectrum. Hence our future work deals with

buckling analysis during landing of an aircraft.

REFERENCES

[1] Curry, Norman S. Aircraft landing gear design: Principles and practices. Washington:

American Institute of Aeronautics and Astronautics, Inc., 1988

[2] E.F. Bruhn, Analysis and design of flight structure, 1973

[3] Hartono Yudo, Aulia Windyandari and Ahmad Fauzan Zakki Numerical Investigation of

the Buckling Strength Behavior of Ring Stiffened Submarine Pressure Hull. International

Journal of Civil Engineering and Technology, 8(8), 2017, pp. 408–415.

[4] Sai Kumar Anisetti, Torsional Buckling Response of Open Cross Section Structures Lying

on Winkler-Pasternak Soil via Dynamic Matrix Method, International Journal of Civil

Engineering and Technology, 8(8), 2017, pp. 398-407